Oscillation device.



G. .W. PIGKARD.

OSGILLATION DBVIGE.

APPLIUATION FILED MAE. 25, 1909.

933,263. Patented sept. 7, 1909.

, Angl,

E1 zz ZL'/usses: 3 fnvenfarf."

`N UNITED sfr-Aras.

PATENT enrichi.

GRENLEAI" WHI'TTIER Homan, ror AInnenma?, MASSACHUSETTS.

i 'OSCILLATION DEVIGE.

To all wtom it may concern:

Be it known that I, GREENLEAF Wnrrrmn PICKARD, a citizen of the, United States-of America, and a resident of Amesbury,- Mas.- sachusetts, have invented certain new and useful Improvements in Oscillation-Detectors, the principles of which are set forth in the following specification and accompanying drawing, 'which disclose the form fof the invention which I now vconsider to be thel 4best of the various forms in which the prinl ciples of the-invention may be embodied.

This invention relates to improvements in oscillation dectectors of the rectifying type employing substantial perfection of circuit. j contacts with the rectifying conductor.

The object of the invention is to obtain a device which shall be very stable, electrically or mechanically, and preferably both, in addition to being sufficiently sensitive for all practical purposes. j

The invention consists of the novel featureslofthe subject matter hereinafter disclosed, and illustrated in the accompanying drawingsof an exemplication embodiment, which drawings are drawn to scale. y

Of the drawings, Figure 1 is an elevation of the complete device lacking only the 'rectifying element; Fig. 2 is a plan of the complete device including the rectifying compound mechanical element shown also in plan in Fig. '3; and Fig. 4 `is a plan ofthe mold for producing the element of Fig. 3.

The operating p arts may be mounted on the hard rubber baseR, suitably formed, as shown in dotted lines, to receive and retain them. The detector may be connected `by the binding posts S, T (Fig.- 2) in any de sired oscillation circuit, such for example, as those used in receiving installations of radio. telegraphy and telephony. The binding post S is connected, as shown, to the con- I 1 tact-location-adjusting portion of the device, (at the left, Figs. l and 2), including the metallic sur-base C, the cup B with adjusting screw N, A the clamping post and screw V, W, and the retaining screw. V1 for base C. The binding postl T1 is connected, as shown inFig. 2,' to the contact-pressureadjusting and maintainingportion of the device, (at the right, Figs. 1 and 2), including the support A for the steel spring K carrying brass point J above .cup Bi, and the adjusting screw E. y The conducting point J (as of a metal, yas brass, Fig. 1), is

-to make.' substantially j perfect and minute l Specification of'Ifetters Patent. y A 'Appncationmee luchas, isos.' serial 110.4815338.

but light contact with the're'ctifying .con-

ductor P (Fig. 2), but the poi-nt J is tobe restrained from doing certain other things, aswill be specified.

\\ .All the'parts of Fig. lare of brass, eX-

cept the steel spring K, the vrubber base-R, andthe rubber head H ofthe adjusting screvir E.

The principal features of the invention fc'omprise an oscillation detector comprising a crystallized iron pyrite element,'and a peculiar combination of this particular rectiity-ing conductor. with certain means for obtaining a'nd maintaining an operative contact adjustment,l especiall devised to be adapted to certainpeculiarities of said rectilfying conductor.

I "have found that while an iron pyrite crystal, or a fragment, is in some cases a .very eiiicient rectifier, yet it not only general-ly has very'few sensitive spots, but that a, contact adjustment like that employed for other rect-,ifiers is so unstable that the substance as so used seemed to have little practical value in a detector. Continued'investiation, however, showed that this unstarather 'tha-'n electrical disturbances, and finally lI discovered that when provision was made to gu'ard against the various adverse conditions of contact-variation by mechanica this substance developed a totally unex ected property, not only of mechanical sta ility, but also of electrical stability, such as not to be affected by the most severe neighboring electrical disturbances. In the first place the iron pyrite frequently requires a very light, although substantially perfect, contact between its bright clear surface and the point f threads, (sixty to eighty per inch), but the Patented sept.' 7, 1909.

j ility was due to the effectV of mechanical.`

shocks, as by the construction to be describe ,is

J. This Apressure is as low as fifty to a hunscrew E, in connection with spring K and support A, has the greatest possible rigidity and permanency of adjustment. Of course, support/A is firmly secured to base R by screw G and pin I, and the right end of spring K is firmly secured to support A by screws U arranged and located as shown,

(Fig. 1). But also the threaded left end of sur-base A (shown in dotted line in Fig.' 2 is slotted at O, and provided with a screw (Figs. 2 and l) for tightening A around screw E to hold the latter from any possible loosening or movement by mechanical jars. Thus the contact pressure will remain c011- stant, and the fairly stiff (but delicately adjustable) spring K will coperate with the other parts to tend to prevent even any vibration of the point'J by mechanical shocks. Also, even if point J should vibrate a little, it must return to rest at the same adjusted position-by virtue of other features to be described, and that position will be on the same point of the pyrite P, (Fig. 2), because that is held absolutely stationary.

In investigating the causes of instability I found that the iron pyrite was not only extremely sensitive to variations in contact pressure, but also to lateral variations of the contact point J. Hence not only is the leaf spring K, which is presented broadside to iron pyrite P, designed to have considerable width, as shown in Fig. 2, but the screw E slides freely throu h unthreaded hole E2 in steel spring K an engages the spring only by a shouldered part El. Thus the oint J, riveted or soldered to the left end o spring K, can be adjusted to pyrite member P with the greatest nicety of perfect contact through the coperation of the elasticity of the spring K and the ineness of the threads of screw E,

t and concurrently, this delicate adjustment is maintained by the rigidity of coperation of j parts A, K and E, irrespective of mechanical jars to the entire holder.

The fragment of iron pyrite crystal is preferably so disposed that a fracture face shall be exposed to the point J, in order to obtain maximum sensitiveness. This is not so much to obtain a rough surface to present minute contact points, (in fact the most etiicient fracture face 'usually consists of smoothly curving brilliant surfaces), as it is 'to obtain a fresh clean surface in -order to secure substantial perfection of contact with point J, which should also be bright and clean, to the same effect. Preferably the surface of the fracture face is as smooth as possible; and if desired the surface may be a polished surface.

The mechanical stability of this iron pyrite detector is such that its operation seems independent of all ordinary vibrations to which it may be subjected, even .including gun-fire on battle-ships. Its electrical stability is such that apparently it need be neither disconnected from radio telegraph 4circuits nor short circuited or otherwise protected, when transmitting, and that it is not disturbed or put out of adjustment by the most severe atmospheric discharges of electricity. I do not know the reason for this electrical --stability, and I do not know why the most effective contact between the cleau` ing specific properties like lron pyrite. 'The invention relates also to other improvements, described below, which are employed with the iron pyrite detector, but which may also be employed-with other rectifying substances as elements of detectors.

The cup B (empty in Fig. 1) is adapted`to receive the molded block M of Fig. 3, as shown in plan in Fig. 2. This block M is made in numbers in'molds such, as that of Fig. 4, similar to the old-fashioned bullet molds, except that the block M is preferably cylindrical, to fit nicely in the cup B. The flasks of Fig. 4 are referably of steel, so that at least the sur aces of the molds M1 may be of steel so as not to be wetted by the fluid metal, which is` preferably any readily fusible alloy, termed soft metal, as well known. Before the metal has set in the mold, the rectifying conductor P is placed in it so as to be permanently incorporated with the block M of the soft metal.

' The compound rectifying element of Fig. 3 is of importance in that it not only rovides a convenient form for shipment ofp the replacement part, Whiclrdform is also adapted for direct use in the detector holder of Fi 1, but also that it, as a replacement part, 1s entirely independent of any permanent part of the holder, and is therefore freely removable from the holder without removing the cup B. The molded junction of rectifier P with block M provides the requisite extended and substantially perfect contact which coperates with the minute contact of P with J to produce the rectifying action. The good and extended contact which I have heretofore obtained between the soft met-al and the cup by molding directly and permanently in the cu is obtained by the cup- Vscrew N (Fig. 1 whereby the block M 1s tightly pressed to the left against the inner wall of the cup B. The inner diameter of cup B is preferably only a thirty-second of an inch larger than the outer diameter of block M. As shown iii-Fig 2, the flan e B1 of cup Bis slotted at L to embrace post so j thatI the cup B may be adjusted in a horizontal plane by partial oscillation and also by radial movement over the right-hand enlarged surface of metallic 'sur-base or support C. The screwjlV serves to clamp flange B1 to sur-base C and thereby obtain good circuit connection of conductor P with a wire under binding screw S (Fig. 2).'

Iron pyrite of the exposed effective area illustrated in Fig. 2, and of the particular samples so far` employed by me, usuall has only two or three spots of marked efi-1 ticiency, these being of small area and each including only a few contact points. In operation, it may require several minutes to find the best spot and the best ladjustment of screw E for the best point of contact in that spot. v"The advant-age ofthe device however, including the combination of the iron pyrite with the special contact adjustment means disclosed, is that when once that proper adjustment is obtained, it will remain constantly operative for indefinitelyl long periods. Prior to myim rovements, the benefit of the electrical stab1lity of this conductor was not had or recognized, because ordinary mechanical shocks andjars com-v pletely impaired the mechanical adjustment, both directly and laterally, so as to'make the conductor practically inoperative, and to make it impossible to observe whether or-not it possessed any valuable electrical stability.

This detector is more ellicient than any other known to me, as to rectifying oscillations received from a nearby or powerful transmitter, and is therefore particularly adapted for short distance communication, of the order of tens or hundreds of miles, as distinguished from thousands of miles; particularly when, as usual, the place of use is subject to mechanical vibrations and electrical disturbances. It is also most useful for long distance work, (asjit is extremely sensitive), particularly by reason of its electrical stabi ity, thus adapting it for use by those not skilled in the art. ,Thus this detectorwill frequently stand direct connection to the transmittin` antenna without disturbance of its operat1ve adjustment. In this connection, the value of this detectorvat times and seasons of atmospheric disturbs ance will be readily understood.

The expression iron pyrite used in the claims, refers to crystal ized or any operative iron pyrite, not only to a complete crystal but to afragment, as disclosed.

I clailn: y

l. An oscillation detector, which comprises the iron pyrite P, means for holdin it stationary, the steel leaf spring K fixed near one end to be presented broadside to pyrite P, the metal point J attached to the lower side of the other end of :spring K to Y gaging sai engage'the .surface of pyrite P, `and the adjisting screw E passing freely through hole l in sp1-lng K and having shoulder E1`ensprmg. I y

2. An oscillation detector, lwhich comprises a fragment of iron pyrite, a support therefor, a caf-spring presented broadside to the contact surface of the pyrite, an adjustin screw passing freely through a hole in sai spring, said screw having a shoulder engaging the :prin and a common support for the spring an screw.

3. An oscillation detector, which comprises a fravment of ironfpyrite, a sup ort therefor, a leaf s ring presented broadgide to the contact sur ace of the pyrite, a threaded support, and an adjusting screw passing `freely through a hole in said sprin and engaging the threads of said threade support, said screw having 'a shoulder engaging said spring. I 4. n osc1llat10n detector, whlch comprises a fragment of iron pyrite, means for holding the same stationary, a leaf-spring arranged to present its broadside to the surface of the pyrite, 'and an adjusting screw for said leaf-spring.

5. An oscillation detector, vwhich comprises a fragment of iron pyrite, means for holding the same'stationary, a leaf-.spring arranged to `present its broadside to the surface of the pyrite, an adjusting screw for said leaf-sprang, and means for holding said adjusting screw stationary in its adjusted position.

6. An oscillation detector holder, which comprises a metallic support, a flanged cup adjustable upon said support, a screw clamping the flange of said cup to the support, a contact member carried opposite the support, by a leaf-spring which is flexible to and from the support, a screw for adjusting the spring, and a clamp to hold the screw in its adjusted osition.

7. An oscil ation detector holder, which comprises a etallic support, a metallic cup 4having a slotted flange, a post engaging the -slot in the flange, and a screw operating on the post to clamp the cup-flange to the support.

-8. An oscillation detector, which comprises afragment of iron pyrite, means for holding the same stationary, a delicately adjustable s ring flexible toward the effective surface o the pyrite, a delicately threaded adjusting screw for said spring, and means for clamping said screw in its adjusted position.

. 9. An oscillation detector, which comprises a fragment of iron pyrite, a leafsprinoarranged to present its broadside to the e ective surface of said pyrite, a delicate ad'usting screw for said spring, and means or holding said adjusting screw in its adjusted position.

10. An oscillation detector, which comprises a fragment of iron pyrite,` means for oldin the same stationary, a delicately adjusta le spring iiexible toward the effective surface of the 'pyrite, a delicately threaded adjustin screw for said spring, and means for'holing said adjusting screw in its adjusted position.

11. A holder' for a rectifying oscillation detector, which comprises a su port for the rectifying conductor, a delicate adjustable spring flexible toward the sur 'ace of said conductor, a delicately threaded adjusting screw for said spring, and a threaded clamp en a in the sprin and ad'ustable to hold g g g J sald spring in its a usted position.

12. A holder for a rectifying oscillation i detector, 'which comprises a support for the rectiying conductor, said sup ort` being radially and circumferentially a justable in j the plane of the surface of the rectiiiyingv conductor, and means for fixing` said supi port in its adjusted position.

13. In an oscillation detector, 'the combination with a rectifyin conductor; of' a conductino` base; a con ucting holder for said rectiFying conductor, said holder being adjustably movable on said base; means for securing said holder in any of its adjustedl positions and in good contact with said base; a leaf-spring carrying a contact member coperating with said rectying conductor, said spring being flexible with respect to said rectifying conductor; and means for nation with a recti ing conductorhavin t considerable effective contact a conducting su port thereforwhich is freely adijustable 1n a plane parallel to that of the e ective surface of said conductor; means for securing said conductor in its adjusted position and in good circuit contact; aleaf-sp'ring flexible to and from the effective surface of said rectifying conductor and its plane of adjustment, said sprin carrying a Contact member copcrating witg said surface of said conductor; a screw and screw-support 'for delicately var ing the ilexure of said spring;- and means or securing saidscrew in its adjusting position.

GREENLEAF WHITTIER PICKARI).

In presence of- EDWARD H. HOWELL, -MYRA S. ROWELL. 

